Rotary pendulum-bob.



GRIVOLAS.

ROTARY PENDULUMBOB. APPLICATION FILED JAN. 11, 190s.

Patented Oct. 26, 1909.

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UNET SALEB @AVENTE FFBJB.

CLAUDE GBIVOLAS, 0F ST. CLOUD, FRANCE.

ROTARY PENDULUlVl-BOB.

To all whom it may concern.-

Be it known that I, CLAUDE GinvoLAs, a citizen of the French Republic, residing at St. Cloud, in France, have invented a certain new and useful Improvementin Rotary Pendulum-Bobs, of which the following is a specification.

Torsional pendulums hitherto constructed for working with a long swing have bobs which perform a reciprocating rotary movement and are suspended by means of thin steel ribbons. rlhe regulation of these pendulums is effected by means of external weights adapted to be adjusted relatively to the center of the bob. This method has the disadvantage that the regulating device is exposed to dust and atmospheric influences.

The present invention provides a regulating device located in the interior of the bob. This arrangement has the advantage that the regulating device is protected from external infiuences, and it also obviates error in the adjusting of the mechanism.

The invention is illustrated in the annexed drawing, in which- Figure 1 is an elevation of a torsional pendulum bob constructed accordinsT to the invention, Fig. 2 a vertical section of the same, Fig. 3 a view of the cover or case thereof, with the base removed, Fig. t a top plan' view of the base, and Fig. a cross-section on the line 5-5 of Fig. 4t.

The pendulum comprises a disk shaped box or case comprising a cover A having a circular fiange A2 (Figs. l, 2 and and which may be swaged, cast or constructed of a cylindrical part soldered to a disk, and a base B which fits into said cover A. Nithin the case a cylindrical supportor block D is fixed to the cover thereof by means of a screw C, and a screw E passes from the said support through the top of the cover and serves for fixing to the latter a external part F, which may be of any suitable ornamental design. To the top of the part F is attached the thin steel ribbon G by means of which the bob is suspended.

The block D is traversed by a steel spindle H screw-threaded outside said block, the thread H1 beine` a right-hand thread and the thread H2 a left-hand thread. The spindle H has a circular groove H2 engaged by the part l of a bolt Il screwed into the block D, so that the spindle can be rotated but not longitudinally displaced.

Vith the threaded parts H1 and H2 of the Specification of Letters Patent.

Application filed January 17, 1 908.

Patented Get. 26, E909.

Serial No. 411,352.

spindle there engage the internally threaded weights J1 and J2 adapted to be simultaneously moved to or from the center of the case A by rotating the spindle. For rotating the spindle a key is placed on the squared end H4 thereof. The flange A2 has a small aperture A1 for the insertion of the key, and two -arrows are engraved adjacent this aperture, marked on the case with letters such as B and A respectively to indicate the directions in which the key must be turned for producing acceleration and retardation respectively Fig. l).

The preliminary or approximate regulation is effected by fixing weights K and K1 at the internal circumference of the base B, the said weights K and K1 being preferably of lead and of the shape shown in Fig. 4; so that they do not interfere with the movements of the weights J1 and J2. The weights K and K1 are fixed by means of screws L L1 which traverse the bottom cover B. The said weights are preferably covered by plates M and M1' of the same shape as the weights, consisting of copper or other rigid metal, and firmly held in position by means of screws. l

Before the parts K, K1, M and M1 are placed in position the adjustable weights J1 and J2 are moved to their central positions, that is to say, positions half-way between the circumference and center of the case. The pendulum is then approximately regulated by adding to or subtracting from the weights K K1. -Precise regulation is then effected by adjusting the weights J1 and J2 in the manner hereinbefore described.

That l claim as my invention and desire to secure by Letters Patent of the United States is :H

1. In a torsional pendulum bob for a clock movement, the combination of a hollow casing extending in the plane of oscillation and symmetrical about the axis of torsion, roughadjustment weights within said casing near the periphery thereof and symmetrical about the axis of torsion and line adjustment weights movable to and from the axis of torsion also within the said casing.

2. In a torsional pendulum bob for a clock movement, the combination of a hollow casing extending in the plane of oscillation and symmetrical about the axis of torsion, rough adjustment weights within said casing near the periphery thereof and symadjustment weights within said Casing near the periphery tlleieo't and symnietl'i al about the axis of torsion and line adjuetnient Weights movable to and from the axis of 15 torsion also within the Said easing.

In witness wbei'eotf I have Signed this Specification in the presence of two witneses.

CLAUDE (irl-HVOLAS. ritnesses DEAN B. MASON,

Lox GRIVoLAS. 

